1. Field of the Invention
This invention relates to a film transporting apparatus, and is particularly concerned with a film transporting apparatus for transporting a film with a plurality of images recorded thereon in a predetermined direction and for positioning the film in a predetermined position.
2. Description of the Related Art
Well known hitherto is a photoprinter for printing out film images on photographic printing paper by irradiating images recorded on a negative film with exposing light and irradiating the light passing through the film images onto photographic printing paper. The photoprinter is provided with a film carrier as a device for carrying films, the negative film with the images to be printed out recorded thereon being set in the film carrier.
This type of photoprinter operates by transporting the negative film placed in the film carrier forwards and backwards. The exposure conditions of each image of the negative film are established and recorded during the forward transportation, along with the position of each image on the film against the marker of the film perforations. On the backward transportation each image is placed in sequence according to exposure position based on the recorded exposure conditions and position of each image recorded during the forward transportation, and is then printed onto photographic printing paper.
With this type of photoprinter, it is necessary that the perforations detected during the forward transportation and the perforations detected during the backward transportation on the film carrier be matched with each other. Hitherto, the last perforation detected during the forward transportation has been regarded as matching the first perforation detected during the backward transportation. Using the first perforation detected during the backward transportation as a reference, the perforation locations during the forward transportation have been matched to the perforation locations during the backward transportation.
However, as is shown in FIGS. 8A and 8B, depending on where the rear edge of the negative film N is cut, the perforation 110 may either not connect with the edge of the negative film M1 (FIG. 8A), or may connect with the edge of the negative film M1 (as in FIG. 8B). Consequently, in the conventional film transporting apparatus, even though the perforation 110 at the rear edge of the negative film may have been detected during the forward transportation, depending on factors such as whether or not the perforation 110 is picked up by the perforation detection sensors, the perforation 110 might not be detected during the backward transportation. In such cases, the problem of being unable to accurately place each images exposure position during the backward transportation arises because the perforations during forward and backward transportation were not able to be matched.